Recently, natural van der Waals heterostructures of (MnBi2Te4)m(Bi2Te3)n have been theoretically predicted and experimentally shown to host tunable magnetic properties and topologically nontrivial surface states. In this work, we systematically investigate both the structural and electronic responses of MnBi2Te4 and MnBi4Te7 to external pressure. In addition to the suppression of antiferromagnetic order, MnBi2Te4 is found to undergo a metal-semiconductor-metal transition upon compression. The resistivity of MnBi4Te7 changes dramatically under high pressure and a non-monotonic evolution of \r{ho}(T) is observed. The nontrivial topology is proved to persists before the structural phase transition observed in the high-pressure regime. We find that the bulk and surface states respond differently to pressure, which is consistent with the non-monotonic change of the resistivity. Interestingly, a pressure-induced amorphous state is observed in MnBi2Te4, while two high pressure phase transitions are revealed in MnBi4Te7. Our combined theoretical and experimental research establishes MnBi2Te4 and MnBi4Te7 as highly tunable magnetic topological insulators, in which phase transitions and new ground states emerge upon compression.

中文翻译：

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反铁磁拓扑绝缘体中压力引起的拓扑和结构相变

最近，(MnBi2Te4)m(Bi2Te3)n 的自然范德华异质结构已被理论预测和实验证明具有可调谐的磁性和拓扑非平凡的表面状态。在这项工作中，我们系统地研究了 MnBi2Te4 和 MnBi4Te7 对外部压力的结构和电子响应。除了抑制反铁磁有序之外，还发现 MnBi2Te4 在压缩时经历金属-半导体-金属转变。MnBi4Te7 的电阻率在高压下显着变化，并且观察到 \r{ho}(T) 的非单调演变。在高压状态下观察到的结构相变之前，证明了非平凡的拓扑结构仍然存在。我们发现体积和表面状态对压力的反应不同，这与电阻率的非单调变化一致。有趣的是，在 MnBi2Te4 中观察到压力诱导的非晶态，而在 MnBi4Te7 中显示出两个高压相变。我们结合理论和实验研究将 MnBi2Te4 和 MnBi4Te7 确立为高度可调的磁性拓扑绝缘体，其中相变和新基态在压缩时出现。